Acrocephalosyndactly (Apert's syndrome): Temporal bone findings.

The middle ear and ossicular chain were not complete in the specimen, but the remnants present appeared normally developed except for the stapediovestibular joint region. The annular ligament was incompletely developed in two areas where fixation by undedifferentiated cartilage occurred. The subarcuate fossa, normally filled with fibrous tissue and usually narrowed by a rim of newly deposited periosteal bone at birth, was unusually large. Included in this fibrous tissue were remnants of the primary cartilaginous capusule undergoing absorption, as well as islands of partially removed endochondral bone. The abnormalities in both instances indicated a disturbance in maturation or resorption of the embryonal cartilaginous capsule.